As late as Wednesday evening, no one in the U.K. government was prepared to definitively say that Theresa May will return to Brussels on Thursday to try and rescue the Brexit negotiations.

When the Democratic Unionist Party, her Northern Irish parliamentary allies, torpedoed the deal she thought was in the bag on Monday, U.K. officials said she would be back in Belgium on Wednesday to smooth things out.

That didn’t happen and time is running out.

If there is no agreement by close of play Friday, senior EU officials said, there is only a slim chance that European Council President Donald Tusk and member countries will be able to prepare guidelines for the transition to trade talks in time for approval at next week’s summit of EU leaders.

A deal could be reached next week and sufficient progress declared at the summit, but it might be a hollow victory for May. If the EU’s guidelines for phase two talks are not in place, weeks or even months could be lost with no talks on transition. The timetable for a transition deal — all-important for British businesses — would slip, with the risk that many firms would trigger contingency plans to move jobs and investment out of the U.K..

May has not been idle since Monday’s setback.

The British side are sticking to what May said on Monday, one senior official said: “We will reconvene by the end of the week.”

Another U.K. government official who spoke to POLITICO on condition of anonymity said the view in the negotiating team was that the Friday deadline was not set in stone.

“It’s about political will,” the official said. “If we came back with a deal on Monday they could do it. The guidelines are practically done anyway. Even if we came back Wednesday it might be possible.”

Political will

Privately, U.K. officials believe a special meeting of the General Affairs Council — foreign affairs or Europe ministers from the EU countries who lay the groundwork for summits of EU leaders — could even agree the negotiating guidelines a week after the Council, should that be required.

“Everyone wants progress — them as much as us. It really is about political will at this stage. That said, we do have to get our own house in order first, that’s true,” the government official said.

Others appeared to be taken by surprise by the suggestion that the EU could grant sufficient progress but not proceed to talks about the U.K.’s future relations with the bloc. It would be a “strange option,” said one government minister.

May and Juncker prepare to give a press briefing on December 4 | Olivier Hoslet/EPA

Bernard Jenkin, one of the leading Brexiteers on the Conservative backbenches, branded the apparent deadline an “EU negotiating tactic” and urged May not to be “intimidated.”

But Anna Soubry, a Tory MP and one of the most outspoken supporters of a close post-Brexit relationship with the EU, said the urgency of moving to phase two of talks should push May into “rubbing out her red lines” and reaching a “realistic deal.”

Soubry has called for the U.K. to effectively remain in the customs union and the single market — both of which the government has ruled out.

A former business minister, Soubry added that British firms were “increasingly frustrated by the lack of progress” in the talks. Business lobby groups like the CBI and TheCityUK have called for a transition deal to be secured as soon as possible to prevent businesses in the U.K. moving investment and staff across the Channel to guarantee continued single market access.

“The Conservatives are the party of business — time to prove it,” Soubry said.

May has not been idle since Monday’s setback. She made two key phone calls Wednesday; one, in the morning, to DUP leader Arlene Foster and another in the afternoon to Irish Prime Minister Leo Varadkar, but with no clear sign of a breakthrough.

She told Varadkar her government was “working hard to find a specific solution to the unique circumstances in Northern Ireland that respects the integrity of the U.K., the European Union and the Belfast [Good Friday] Agreement.”

The split also runs through the Cabinet.

Varadkar agreed to speak to May again in the coming days, Reuters reported. Earlier in the day he had done little to raise British hopes of a speedy resolution by confirming talks could always be picked up “in the new year.”

That prompted anger from the DUP, who blame the hold-up on Dublin. Their deputy leader, Nigel Dodds, said delays to trade talks threatened the Irish economy more than the U.K.’s.

“Mr. Varadkar may try to appear calm on the surface but he is playing a dangerous game — not with us but with his own economy,” Dodds said, further ramping up his party’s criticism of Varadkar’s government.

The home front

At home, the simmering tension within May’s Conservative party over the kind of Brexit the U.K. should be pursuing — soft or hard, close to EU rules or free to strike out alone — has broken out into open warfare.

At Prime Minister’s Questions in the House of Commons, Brexiteers teamed up to turn the screws on May.

Jacob Rees-Mogg asked her to “apply a new coat of paint to her red lines” which on Monday had begun to look “a little bit pink.”

Jenkin warned her not to keep the U.K. “shackled” to EU rules for fear of compromising future trade deals with Canada, Japan, the U.S. and Australia. Peter Bone asked quite openly if the government’s planned Brexit, which he had previously endorsed, was “still on course.”

Delegates attend the first day of the annual Conservative Party conference on October 1, 2017 in Manchester, England | Carl Court/Getty Images

More quietly but no less forcefully, the Conservatives’ soft Brexit faction lobbied the prime minister via a letter, signed by 19 MPs and seen by Buzzfeed, expressing disappointment that “yet again some MPs and others seek to impose their own conditions on these negotiations.”

The split also runs through the Cabinet. Philip Hammond, the chancellor, the most prominent figure on the soft Brexit wing, confirmed to MPs on Wednesday that the Cabinet is yet to have a “specific mandating” discussion on the “end-state” relationship the government is seeking with the EU.

That will happen by the end of the year, Downing Street confirmed Wednesday evening, risking a showdown between Hammond and his allies with advocates of a more detached relationship with the EU such as Foreign Secretary Boris Johnson and Environment Secretary Michael Gove.

Whether it will take place in the happy context of a deal on phase one of the Brexit talks or amid a crisis over no deal being struck depends on the offer that May takes back to Brussels — and how soon she gets there.